Geoscience Reference
In-Depth Information
veriication of receipt of warning notiications by local emergency managers. Within minutes of
the initial notiication of the CSWC by the WC/ATWC, Ofice of Emergency Services (OES) staff
were paged and instructed to verify that the notiication was received by the local government
emergency managers. This veriication process was not able to be completed in the northern
most counties (those directly impacted by the earthquake and with the greatest potential for
being affected by a tsunami) where telephone service was limited by excessive local use after
the earthquake and where hundreds of residents had called 911 dispatch centers to report the
earthquake. In Crescent City, Del Norte County, a single 911 dispatcher was overwhelmed by
the call volume and was not able to receive calls from state personnel verifying receipt of the
tsunami warning.
Given the short time span in Humboldt and Del Norte counties between earthquake
shaking, issuance of the tsunami warning by the WC/ATWC, and possible tsunami wave arrival,
this demand made it dificult for the CSWC and OES to expedite the warning process, a prob-
lem that was exacerbated by overloaded wire and cell telephone systems, inadequate stafing
at the state and local government emergency operations centers, and limited training at the
local government level.
Despite the confusion that was prompted by the conlicting message sent by the Paciic
Tsunami Warning and Mitigation System (PTWS), the CSWC transmitted only the irst TWC
(from the WC/ATWC) warning using CALWAS. The NWS, following NOAA procedure, activated
the Emergency Alert System (EAS) and broadcast the tsunami warning to the potentially im-
pacted counties.
Six minutes following the transmission of the tsunami warning, the CSWC held a confer-
ence call between the OES Costal Regional Administrator and earthquake/tsunami specialists
to remediate the confusion with personnel from counties that might be impacted. As noted
above, overload of the local telephone system precluded OES staff from making contact
with local oficials in Humboldt and Del Norte counties. The state's satellite telephone system
(OASIS) linking OES regional ofices and county PSAPs could not be immediately utilized be-
cause it could not be accessed from staff residences (the event occurred when OES region staff
were at home, as were most local government oficials).
Another element of the states' communication procedures with local governments is the
convening of conference calls between local government emergency managers, state oficials,
and appropriate hazard experts at the time of the issuance of alerts to local government. The
state maintains multiple 30-port conference bridge lines for this purpose. Attempts to use the
conference call procedures at the time of the tsunami warning were unsuccessful because
inbound lines with the scientists at the WC/ATWC were overloaded and local government of-
icials could not be contacted.
As noted above, the population of the impacted areas in northern California was “notiied”
by the earthquake, by broadcasts over the NOAA All Hazards Radio system, and by stations
participating in the EAS. In Crescent City, the tsunami sirens were not sounded until 8:30 PDT
(0330 UTC) because of the telephone saturation of the 911 dispatch center and the inability of
the single staff person on duty to handle conlicting workload priorities. Spontaneous evacu-
ations took place in several communities. In many of the northern California communities,
